Answer: Lily of the Nile is Agapanthus. It produces large clumps of long, straplike leaves. Calla is Zantedeschia aethiopica. It's leaves are more triangular in shape and it is usually a smaller plant, perhaps about one foot in height and width.
These plants are somewhat marginal for our low desert. Both would do best with protection from afternoon sun, especially in summer. They require regular water and fertilizer during the growing season and soil rich in organic matter. To encourage bloom, scratch a phosphorous source such as bone meal into the soil to the side of the plant and water thoroughly. I hope this info helps.
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